Research On The Password System Using Chaos Mapping And Block Cipher

With the rapid development of computer technology the storage, transmission，and processing of the digital information are more and more convenient, and alongwith the network popularization, the transmission and application are also updatedquickly. In information security system, the safety and secrecy of the information isespecially important; the password is the most basic method and the key technologywhich ensures the security of information. As the properties of the chaotic dynamicalsystems are consistent with the requirements of traditional cryptography, a newbreakthrough emerges. And as the result of the occurrence of the hot topic based onthe nonlinear science chaos theory in the past20years, the research on chaoticcryptography becomes important.Chaos sequence computing is more complex, which makes it more difficult topredict the initial value. At the same time, the properties of the chaotic system, thedeterminacy and the complex randomness, are particularly suitable for theapplication in the field of secure communications and information security. Threechaotic cryptography problems need to be resolved, namely: short-period response;finite precision effects; contradictions between realizing accuracy andconfidentiality.Based on the former cryptography study, this paper focuses on the analysis anddesign of chaotic block cipher, and in this new algorithm, the piecewise linearchaotic map and the block cipher group theory are combined to prove mathematicalrigor theoretically. The function is to make the transformation of the existing chaosdiscrete and send it to finite state space, and through its and its inversetransformation of chaos, the plaintext can be encrypted and decrypted and thechaotic maps can be discrete correspondingly. In the new algorithm chaoticpasswords and regular password are combined, and the password is no longer asingle system, and with their respective advantages, the key space is expanded; thealgorithm complexity is improved; the anti-attack capability and security areenhanced greatly.